Abstract
Shoot apical meristem (SAM) of plants shows a well-organized spatio-temporal order, despite active cell division and continuous production of aerial tissues. Molecular mechanism of SAM has been extensively studied, and SAM is crucially maintained by the feedback regulation between WUS and CLV. However, dynamic behaviors of SAM are still not understood, and its essential understanding requires analysis as a dynamic system. Therefore, we tried to investigate SAM dynamics using methods of theoretical biology. We constructed a mathematical model including four conditions: WUS-CLV interaction, two-dimensional pattern formation, area expansion by cell division, and PZ induction by CZ. First, we intensively examined patterns generated by the model and their detailed parameter conditions. Observed patterns are divided into six classes according to their shape and proliferation. Obtained results are consistent with many known experimental observations in A. thaliana and other plants. From these findings, we conclude that SAM dynamics is essentially governed by two parameters: stem cell proliferation mode (pattern proliferation) and stem cell containment (spatial restriction strength).
